Haltech F10 User Manual download pdf (Page 48)

5.3.4 On the Dyno

Whether the vehicle is on a chassis dyno, or the engine on an engine dyno, the principles of

programming the Haltech F10 are the same. Take the en gine rp m up to 1000 and apply partial

load and adjust the 1000 rpm range. Return the engine to idle and on the 1000 rpm range

adjust the bars to draw a straight line from the idle point through the part load setting tested.

Continue, adding more load, up to the full load settings. This should be a fairly good

approximation to the required curve. Repeat this for the 1500 range, 2000, 2500 etc. The

engine should be fairly drivable at this point.

Full load tuning should be approached with caution. An engine at full load that is too lean

may begin to detonate and destroy pistons and crankshafts. Before loading the engine,

increase the h eights of the right-most bars so that they are higher than the lin e p rojected by

drawing a straight line from the idle and free-rev settings and through the part-load settings.

WARN ING:

RUN THE MAP RICH, AND LEAN IT TO THE CORRECT

MIXTURES. DO NOT RUN THE MAP LEAN AND ATTEMPT TO

ENRICH TO THE CORRECT MIXTURES.

5.3.5 On the Road

Tuning on the road is similar to tuning on the dy namometer, but with hills, acceleration, gear-

ratios and brakes providing the necessary retarding force. Although it is harder to maintain

constant load and sp eed, it is still possible to use the same p rocedure used on the dy no. It will

be necessary to have one person drive while another does the tuning.

Load the engine by selectin g an ap p rop riate gear and either drivin g up a constant grade hill,

applying the brake or handbrake.

WARN ING:

BE VERY CAREFUL USING THE BRAKE TO LOAD THE ENGINE.

THE BRAKES CAN GET VERY HOT AND SUFFER FROM BRAKE

FADE (REDUCED BRAKING CAPABILITY) AND THE CARS

HANDLING M AY B ECO ME UNS TABLE. ALL RO AD T ES TING

SHOULD BE DONE AT LOW SPEED.

5.3.6 Fine Tuning the Engine

When fine-tuning the en gin e for the road, the same p rincip les ap p ly to all en gines. Under full

load at all rpm the fuel mixture should be rich. On non turbo cars an air to fuel ratio of around

12.5:1 to 13.5:1 is usually best (high performance turbo vehicles may go as low as 10.5).

When cruising (light to medium load) the mixture should be as close to stoichiometric (best

mixture) as p ossible and deceler ating conditions may allow the engine to be run lean to save

fuel. This will result in a particular shap e for the map . A typ ical map is shown adjacent. The

absolute values will v ary greatly , but the shap e should be similar.

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Haltech F10 User Manual Page 48